1. Field of the Invention
The invention relates generally to luminaires having reflector and refractor sections preferably formed of light-transmissive material and mated together to form a globe within which a light source is disposed, the invention particularly relating to a bandless seam between said sections and having improved appearance and optical characteristics.
2. Description of the Prior Art
Luminaires intended for both indoor and outdoor illumination have long been known in the art to include combination reflector/refractor light-transmissive xe2x80x9cglobesxe2x80x9d utilizable with a variety of lamping configurations to provide particular light distribution characteristics for a given application. Such reflector/refractor combinations have typically been formed of materials such as glass and plastic materials such as acrylics, etc., and often employ prisms and similar light-altering structures formed on either interior or exterior surfaces, or both, of such prior reflector/refractor combinations. Light is directed in these prior combinations from an associated lamp in a manner providing a desired level of lighting within a space that is to be illuminated. In applications thus referred to, at least the refractor section of the combination is formed of a light-transmissive material such as glass with the reflector section often being formed also of glass or a light-transmissive acrylic material or the like. Luminaire globes of this description are typically either pole-mounted, usually for outdoor applications, or xe2x80x9csuspendedxe2x80x9d for either indoor or outdoor applications. When a luminaire globe of the kind referred to herein is xe2x80x9cpole-mountedxe2x80x9d, support for the globe is typically provided from a location beneath the globe, it not therefore being as necessary to provide a positive attachment between the reflector section and the refractor section since the seam or joint therebetween is not required to support the weight of the refractor section. In suspended applications, it is usually necessary to positively attach the refractor section to the surmounting reflector section such as through the use of a band or other mechanical support. It should be noted, however, that globes used in pole-mounted applications often provide a band at a seam between reflector and refractor sections for increased surety of connection therebetween and/or for the sake of appearance. For example, Ewing, in U.S. Pat. No. Des. 441,115, shows a luminaire globe intended to be supported by a pole from beneath said globe. Ewing also provides a band at the seam between reflector and refractor sections as an element of the appearance of the luminaire as well as for providing an increased degree of attachment therebeween. Other patents disclosing luminaire globes formed of light-transmissive material and being mounted such as at the upper ends of poles or similar stanchions are disclosed by Sitzema et al, in U.S. Pat. No. 5,743,634, and by Orosz, in U.S. Pat. No. 4,719,548, the disclosures of these patents being incorporated hereinto by reference. Sitzema et al particularly disclose a reflector/refractor combination formable of either glass or acrylic materials and wherein a pole or the like supports the refractor for mounting of the reflector thereto, there being no need therefore to support the weight of the refractor with a band formed about a seam or joint between the reflector and the refractor. However, Sitzema et al disclose the use of an adhesive to adhere the reflector to the refractor. In Sitzema et al, adhesive is not employed to attach the refractor directly to the reflector such that an adhesive joint is the sole mechanism for preventing detachment between the reflector and the refractor. Orosz attaches a refractor to a surmounting reflector through the use of an adhesive and screws even though the Orosz luminaire is mounted by a pole.
Arumugasaamy, in U.S. Pat. No. 6,336,734 and also in U.S. Pat. No. Des. 4,040,341, discloses a glass reflector/refractor combination in a suspended luminaire and having a band employed at a seam between the reflector and the refractor for supporting the weight of the refractor. Arumugasammy illustrates the manner in which the use of a band can be incorporated into the appearance of a suspended luminaire in an effective manner. Other United States design patents having similar disclosures are issued to Ewing et al, as U.S. Pat. No. Des. 400,273; Gruber et al as U.S. Pat. No. Des. 350,622; and to Hughes et al as U.S. Pat. No. Des. 321,408. In U.S. Pat. No. 5,174,648, Clary et al disclose a suspended luminaire having a glass or acrylic globe with a band formed about the seam therebetween for supporting at least in part the weight of a refractor portion of the luminaire. Van Steenhoven, in U.S. Pat. No. 3,950,639, mounts a refractor to a reflector by means of a metal ring formed about a seam between the reflector and refractor. Harling, in U.S. Pat. No. 3,329,812, mounts a glass refractor to a metal reflector. Fouke, in U.S. Pat. No. 6,027,231 provides a flange at a seam between a glass reflector/refractor combination, the disclosure of this patent being incorporated hereinto by reference. Similar disclosure is also provided by Fouke in U.S. Pat. No. 4,858,091, the disclosure of which is incorporated hereinto by reference. Luminaire globes comprising reflector/refractor combinations are disclosed by Blondel et al, in U.S. Pat. No. 563,836 and by Franck, in U.S. Pat. Nos. 2,818,500 and 2,887,568, the disclosures of these patents being incorporated hereinto by reference.
As can be appreciated from a review of the patents noted above, it has been common in the art to employ a band or similar structure about a seam between a reflector section and a refractor section of a luminaire globe in order to positively attach the refractor to the reflector especially in suspended situations and, as can be seen from a review of certain of the patents noted above, even in pole-mounted applications. The necessity for the use of a band or similar structure has been ameliorated by the creativity of the designers of such luminaire globes through the agency of causing the bands or similar structure to be decorative. However, the use of a band or the like invariably causes a reduction in lighting performance since light is lost through reflection off internal surfaces of such a band and such bands prevent uninterrupted illumination through the entirety of the refractor section of such a globe. Even in luminaire globes not employing bands, a seam or joint between reflector and refractor sections typically causes glare or optical xe2x80x9cglintxe2x80x9d due to the fact that light passing through the seam produces a line or xe2x80x9cbandxe2x80x9d of bright light that differs from the quality of light passing through the reflector section and the refractor section, said reflector and refractor sections often being provided at considerable expense with prismatic structures intended to produce a pleasing quality of light emanating from the luminaire globe.
In applications where a xe2x80x9ccleanxe2x80x9d appearance is desired, that is, a xe2x80x9cbandlessxe2x80x9d appearance is necessary in order to provide decorative function inter alia, prior approaches to solution of the above-noted deficiencies in the art have not yielded luminaire globe function of a kind acceptable to particular applications when considering appearance and evenness of illumination. An advance in the art would therefore be realized through an ability to attach a refractor to a reflector, particularly for a suspended luminaire, without the requirement for a band disposed about a seam between a reflector and refractor and wherein the seam therebetween is not subject to a high degree of optical glint and/or glare. The present invention therefore intends solution to the deficiencies noted above by providing a seam or joint between a reflector section and a refractor section of a luminaire globe whereby adhesive is evenly applied to opposed mating peripheral edges thereof to reduce brightness at the seam and to provide at least some degree of attachment function at the joint therebetween. Luminaire globes configured according to the invention therefore exhibit a desired physical appearance and produce a desirable quality of illumination.
The invention in several aspects relates to structure and methodology involving a seam or joint between reflector and refractor sections of a luminaire globe such as a globe formed of glass, acrylic or other light-transmissive material. Luminaire globes improved according to the teachings of the invention typically have prismatic or similar light-directing structures on either the reflector section or the refractor section, or both. Luminaire globes that are component parts of suspended luminaires, in particular, must be provided with a mechanism whereby a relatively heavy refractor section is caused to be mounted or attached to a surmounting reflector section, the seam or joint therebetween optically differing from remaining portions of the luminaire globe. Accordingly, the seam visibly differs from remaining portions of the globe and is typically a source of glare or optical glint due to the seam appearing as a bright annular xe2x80x9clinexe2x80x9d extending about the globe.
The invention in its several aspects provides shaped surfaces on mating annular peripheral edges of the reflector section and of the refractor section, these shaped surfaces particularly acting to cause an even flow of an adhesive applied thereto on joining of the reflector and the refractor sections together. This even flow of adhesive causes the seam between said sections to be optically more acceptable due to the existence of adhesive in a uniform disposition essentially throughout the seam, light passing through the seam being caused to be more efficiently passed therethrough and with improved appearance. Further, an even and complete flow of the adhesive over mating surfaces of the reflector and of the refractor permits the formation of a joint of greater strength to the degree that relatively small luminaire globes, even when used in a suspended luminaire, can be mounted together solely through the use of adhesive.
In essential form, the invention minimizes flanges typically employed between reflector and refractor sections of a luminaire globe to the point of permitting a continuous curvature to exist between the reflector and refractor section, that is, to essentially eliminate the appearance of an external flange altogether. The shaped surfaces of the mating peripheral edges of the reflector and refractor sections act to provide a necessary degree of alignment between the reflector and refractor sections as well as to cause uniform flow of adhesive within the joint between said sections. An appropriate sizing and shaping of certain wall surfaces of the structure defining the present seam also functions to reduce glare by directing light passing through the seam above horizontal so as not to be visible from normal locations within an environmental space in which a luminaire employing the present globes are disposed.
Accordingly, it is a primary object of the present invention to provide a seam for a luminaire globe formed of a reflector section and a refractor section wherein peripheral opposed edges of said sections are contoured in order to cause even flow of adhesive therebetween when joined together and to further reduce optical glint and glare due to shaping of at least portions of said section edges defining the seam.
It is another object of the present invention to provide a seam between reflector and refractor sections of a luminaire globe formed of a light transmissive material such as glass, acrylic or the like, and wherein the appearance of the seam is minimized.
It is a further object of the invention to provide a luminaire globe formed of reflector and refractor sections wherein the sections are provided with contoured peripheral edges joinable together to attach said sections without the need for a structural band disposed over the seam for attaching the refractor section to the reflector section.
Further objects and advantages of the invention will become more readily apparent in light of the following detailed description of the preferred embodiments.